A Forgotten Kingdom: The Spanish Frontier in Colorado & New Mexico–1540-1821 by Frederic Athearn, Bureau of Land Management 1989 https://upload.wikimedia.org/wikipedia/commons/2/20/A_forgotten_kingdom_-_%24b_the_Spanish_frontier_in_Colorado_and_New_Mexico%2C_1540-1821_%28IA_forgottenkingdom00athe%29.pdf?fbclid=IwAR3dCK547oYJWNz0pV2mx5YL7EOCiz666ZFWPrGC8m4SLt7tAZwU0M8VXxI